1. Field of the Invention
This invention relates to apparatus for maintaining the hull of a high-powered speedboat in a proper fore-and-aft attitude, particularly when accelerating, to prevent pitching or upending.
2. Description of the Prior Art
In an engine-powered boat, the propellor is generally located below the hull and near the stern. Thus, in high-powered boats, such as are used for racing, the forces exerted by the propellor, especially during acceleration, tend to cause the boat to upend, i.e., for the bow to rise sharply. In drag racing, where the race commences from a dead start, this problem is acute and hazardous.
To overcome the above problem, drag racing boats, as well as ski towing boats and the like, are usually fitted with a cavitation or trimming plate unit which is mounted at the stern for an up-down swinging adjustment under control of the boat driver. As the boat accelerates from a starting position, the driver forces the cavitation plate downwardly to react against the water to resist any upending tendency.
Control of the plate is critical, since if it is overly depressed at high speeds it could cause the bow to dig into the water and if it is under-depressed, the bow could rise excessively. As the speed increases, the plate must be allowed to rise to maintain the hull in a planing attitude. Thus, it will be seen that the driver's judgement is critical and he must react fast and precisely to attain the highest speed in the shortest time period.
In the case of flat-bottom speedboats, the ideal condition for highest speed is one in which the boat is substantially airborne slightly above the water with a layer of air trapped under the hull to support much of its weight. The remainder of the weight is supported at the stern by the cavitation plate which rides on the surface of the water.
Heretofore, control of the cavitation plate was generally accomplished by providing two foot pedals to be manipulated by the driver. Pressure on one pedal against the force of an actuator spring causes downward movement of the plate, and as the boat accelerates, foot pressure is released allowing the spring and the forward movement of the boat to raise the plate to an upper position where it itends to maintain the boat in a planing position. However, since different forces, such as acceleration, wave action, wind, etc., act on the boat, tending at times to move the plate out of this upper position and allow pitching, the second foot pedal is provided to enable manual positioning of the plate against the action of these forces, Since the driver has to use one foot to control the engine throttle, he has to use his remaining foot to quickly shift from one foot pedal to the other and to apply appropriate pressure at the right time. This requires utmost concentration and attention by the driver at a time when other functions and controls must also be attended to.